High-frequency module and wireless communication device

ABSTRACT

A high-frequency module is connected to a transmitting circuit (TX), a receiving circuit (RX) and an antenna (ANT) to control the connections between the transmitting circuit (TX) and the antenna (ANT) and between the receiving circuit (RX) and the antenna (ANT) The module comprises means ( 2 ) for controlling transmitted signals, which includes a first phase-shift circuit ( 5 ) and a high-frequency amplifier ( 4 ) provided between the antenna (ANT) and the transmitting circuit (TX). The high frequency amplifier ( 4 ) and the first phase-shift circuit ( 5 ) are integrated into a module composed of a plurality of dielectric layers.

FIELD OF THE INVENTION

[0001] The present invention relates to a high-frequency composite partused in high-frequency bands such as micro-wave bands, etc.,particularly to a high-frequency composite part for controlling signallines among a transmitting circuit, a receiving circuit and an antennain a high-frequency circuit of a digital mobile phone, etc., and awireless communications device comprising such a high-frequencycomposite part.

BACKGROUND OF THE INVENTION

[0002] Wireless communications devices, for instance, mobile phones havebecome popular remarkably in recent years with their functions andservices improved increasingly. Taking a mobile phone as an example,there are various systems for mobile phones, for instance, EGSM(Extended Global System for Mobile Communications) and DCS1800 (DigitalCellular System 1800) systems widely used mostly in Europe, a PCS(Personal Communications Services) system used in the U.S., and a PDC(Personal Digital Cellular) system used in Japan. In such mobile phonesof digital communications systems, high-frequency switches are used toswitch the connection between a transmitting circuit and an antenna andthe connection between a receiving circuit and an antenna.

[0003] One example of the high-frequency switches is disclosed byJapanese Patent Laid-Open No. 2-108301. This high-frequency switchcomprises a diode placed between a transmitting circuit and an antenna,and a λ/4 phase shift line placed between an antenna and a receivingcircuit, the receiving circuit side of the λ/4 phase shift line beinggrounded via a diode, thereby constituting a λ/4-type switch circuit forswitching signal paths by a bias current flowing through each diode.

[0004] According to recent rapid expansion of mobile phones, however, afrequency band allocated to each system cannot allow all users to usetheir mobile phones in major cities in advanced countries, resulting indifficulty in connection and thus causing such a problem that mobilephones are sometimes disconnected during communication. Thus, proposalwas made to permit users to utilize a plurality of systems, therebyincreasing substantially usable frequencies, and further to expandserviceable territories and to effectively use communicationsinfrastructure of each system.

[0005] In such circumstances, dual-band mobile phones, triple-bandmobile phones, etc. have been proposed as mobile phones having newsystems. While a usual mobile phone comprises only onetransmitting/receiving system the dual-band mobile phone comprises twotransmitting/receiving systems, and the triple-band mobile phonecomprises three transmitting/receiving systems. With these structures,users can choose and utilize available transmitting/receiving systemsamong a plurality of systems. In the dual-band mobile phone and thetriple-band mobile phone, there is a high-frequency switch for switchingthe connection between an antenna and a transmitting circuit or areceiving circuit by time division, so that bidirectional communicationscan be carried out with one antenna shared in transmitting/receivingsystems.

[0006] The inventors already proposed in Japanese Patent Laid-Open Nos.11-225089 and 11-313003 a high-frequency switch module comprising acombination of a branching circuit (diplexer) for separatinghigh-frequency signals of a plurality of frequency bands and ahigh-frequency switch, with a function of switching the transmittingcircuit and the receiving circuit of a plurality of communicationssystems as a high-frequency switch capable of utilizing a plurality ofcommunications systems, the high-frequency switch module beingconstituted by a multi-layered module integrated with the branchingcircuit (diplexer) the high-frequency switch circuit, etc.

[0007]FIG. 21 shows an equivalent circuit of a high-frequency switchdisclosed by Japanese Patent Laid-Open No. 2-108301. To connect anantenna terminal ANT to a transmitting circuit TX, positive voltage isgiven from a power supply means (control circuit) to a terminal VC1.With a DC signal cut by capacitors 70, 71, 73, 74 and 79, positivevoltage given by the control circuit is applied to a circuit comprisingdiodes 77, 78 to turn the diodes 77, 78 to an ON state. With the diode77 in an ON state, there is low impedance between the transmittingcircuit TX and the connection point IP1 . Also, with a diode 78 in an ONstate, the distributed constant line 75 is grounded at high frequencies,causing resonance, resulting in the extremely high impedance of thereceiving circuit RX viewed from the side of the connection point IP1.As a result, the transmitting signal from the transmitting circuit TX issent to the antenna terminal ANT without leaking to the receivingcircuit RX.

[0008] However, because the diode 77 placed in series between theantenna terminal ANT and the transmitting circuit TX acts as a resistorin an ON state, the transmitting signal suffers from large loss. Becausethe diode through which a bias current should flow at transmittingconsumes electricity from the battery, the mobile phone has a shortperiod of communicatable time, resulting in difficulty in achieving lowelectricity consumption. Further, because parts such as diodes andcapacitors for cutting a DC signal are needed, high-frequency switchmodules are constituted by inevitably large multi-layered modules,making it difficult to provide small and lightweight wirelesscommunications devices of dual band or more.

OBJECTS OF THE INVENTION

[0009] Accordingly, an object of the present invention is to provide asmall and lightweight high-frequency composite part for controllingsignal lines between a transmitting circuit, a receiving circuit and anantenna in a wireless communications device such as a mobile phone,etc., which has a simple circuit structure excellent in the insertionloss of a transmitting signal with low power consumption.

[0010] Another object of the present invention is to provide a smallwireless communications device such as a mobile phone, etc. comprisingsuch a high-frequency composite part.

DISCLOSURE OF THE INVENTION

[0011] As shown in FIG. 1, the present invention provides ahigh-frequency composite part connected among a transmitting circuit TX,a receiving circuit RX and an antenna ANT, comprising a transmittingsignal control means 2 for controlling the connection between thetransmitting circuit TX and the antenna ANT, and a receiving signalcontrol means 3 for controlling the connection between the receivingcircuit RX and the antenna ANT, the transmitting signal control means 2and the receiving signal control means 3 cooperating to switch signalpaths of a high-frequency signal transmitted or received through theantenna ANT.

[0012] An important feature of this high-frequency composite part isthat the transmitting signal control means 2 is constituted by ahigh-frequency amplifier and a phase-shifting circuit. FIG. 2 is a blockdiagram showing the circuit of the transmitting signal control means 2.The high-frequency amplifier 4 has impedance of substantially 50 Ω atwork in a frequency band of a transmitting signal, while it is in asubstantially short-circuited state at a stop in a frequency band of areceiving signal. The first phase-shifting circuit 5 controls the phaseangle of the high-frequency signal.

[0013] Without the first phase-shifting circuit 5, the high-frequencyamplifier 4 has impedance corresponding to a substantiallyshort-circuited state at a stop, so that the receiving signal from theantenna ANT is absorbed by the high-frequency amplifier 4. With thefirst phase-shifting circuit 5, however, the receiving signal from theantenna ANT is phase-shifted, so that the impedance of the transmittingsignal control means 2 viewed from the antenna side becomes asubstantially open state while the high-frequency amplifier 4 is at astop. Accordingly, the receiving signal is sent to the receiving circuitRX without leaking to the transmitting circuit TX.

[0014] Therefore, the high-frequency composite part of the presentinvention is connected among the transmitting circuit, the receivingcircuit and the antenna for switching the connection between thetransmitting circuit and the antenna and the connection between thereceiving circuit and the antenna, comprising a transmitting signalcontrol means comprising a first phase-shifting circuit and ahigh-frequency amplifier between the antenna and the transmittingcircuit, the high-frequency amplifier and the first phase-shiftingcircuit being integrated in a multi-layered module constituted by aplurality of dielectric layers.

[0015] The phase-shifting circuit is a circuit for controlling the angleof a phase moved to control the impedance of the transmitting signalcontrol means and the receiving signal control means at desired levels.The first phase-shifting circuit comprises a distributed constant line.The first phase-shifting circuit may have various structures, and in thesimplest structure the first phase-shifting circuit is constituted by adistributed constant line having such a line length that the impedanceof the transmitting signal control means viewed from the antenna side isin a substantially short-circuited state in a frequency band of areceiving signal.

[0016] The high-frequency amplifier comprising gallium arsenide GaAssemiconductor chips has such impedance characteristics that it hasimpedance of substantially 50 Ω at work in a frequency band of atransmitting signal, while it is in a substantially short-circuitedstate at a stop in a frequency band of a receiving signal. The firstphase-shifting circuit may be constituted by a distributed constant linehaving a line length of substantially λ/4, wherein λ is the wave lengthof a receiving signal, and the line length is an effective length of aline in a spiral or meander type, etc. Because the actual line lengthmay change depending on the wave length-shortening effects of the lineand dielectric constant of a multi-layered module constituting thedistributed constant line, etc., the line length is preferably set in arange of λ/10-λ/4.

[0017] The first phase-shifting circuit in another embodiment comprisesa directional coupler for monitoring part of a transmitting signalamplified by the high-frequency amplifier, and the main line of thedirectional coupler is preferably at least part of the distributedconstant line. The first phase-shifting circuit may comprise a detectorfor detecting part of the branched transmitting signal. In the preferredembodiment, the detector comprises a detecting diode and a smoothingcapacitor, the detecting diode being mounted onto the multi-layeredmodule, and the smoothing capacitor being formed by capacitor electrodesopposing via a dielectric layer inside the multi-layered module.

[0018] In each of the above embodiments, the first phase-shiftingcircuit keeps the impedance of the transmitting signal control meansviewed from the antenna side in a substantially open state in afrequency band of a receiving signal, while the high-frequency amplifieris at a stop.

[0019] The high-frequency amplifier in the high-frequency composite partof the present invention preferably comprises an amplifier circuitcomprising a transistor, an input-matching circuit connected to theinput terminal of the amplifier circuit, and an output-matching circuitconnected to the output terminal of the amplifier circuit, each of theinput-matching circuit and the output-matching circuit comprising acapacitor and an inductor, the transistor of the amplifier circuit beingmounted onto the multi-layered module, and the inductors being formed asdistributed constant lines inside the multi-layered module. Thecapacitor is preferably formed by electrodes opposing via a dielectriclayer inside the multi-layered module. The above transistor is a fieldeffect transistor, and the high-frequency amplifier is made of galliumarsenide GaAs, these parts being mounted onto the multi-layered module.

[0020] In another preferred embodiment of the present invention, thehigh-frequency composite part comprises a receiving signal control meanscomprising a second phase-shifting circuit and a band pass filterbetween the antenna and the receiving circuit, the second phase-shiftingcircuit and the band pass filter cooperating to keep the impedance ofthe receiving signal control means viewed from the antenna side in asubstantially open state in a frequency band of a transmitting signal.Preferably usable as the passband filter is a surface acoustic wavefilter, a multi-layered-type dielectric filter, a coaxial resonatorfilter or a bulk-wave filter.

[0021] In a further preferred embodiment of the present invention, thehigh-frequency composite part comprises a receiving signal control meansbetween an antenna and a receiving circuit, the receiving signal controlmeans comprising a distributed constant line and a diode connectedbetween the distributed constant line and the receiving circuit andgrounded via a capacitor. In the preferred embodiment, the diode ismounted onto the multi-layered module, and the distributed constant lineis formed inside the multi-layered module.

[0022] The high-frequency composite part according to a furtherpreferred embodiment of the present invention handles a plurality oftransmitting/receiving systems of different passbands, comprising aplurality of filter circuits of different passbands connected to theantenna terminal, with a transmitting signal control means comprising afirst phase-shifting circuit and a high-frequency amplifier on thedownstream side of at least one filter circuit. The high-frequencyamplifier and the first phase-shifting circuit are integrally formedinside the multi-layered module constituted by a plurality of dielectriclayers. This high-frequency composite part can be used commonly forhigh-frequency signals for a plurality of communications systems fordual-band, triple-band, etc. in which high-frequency signals of aplurality of frequency bands are commonly used.

[0023] Each of the first and second filter circuits is preferably an LCcircuit comprising an inductor and a capacitor, the inductor beingformed as a distributed constant line inside the multi-layered module,and the capacitor being formed by capacitor electrodes opposing via adielectric layer inside the multi-layered module.

[0024] The first phase-shifting circuit comprises a distributed constantline. The first phase-shifting circuit preferably further comprises adirectional coupler for monitoring part of the transmitting signalamplified by the high-frequency amplifier, the main line of thedirectional coupler being part of a distributed constant line of thefirst phase-shifting circuit. The first phase-shifting circuit mayfurther comprise a detector for detecting part of the branchedtransmitting signal. The detector comprises a detecting diode and asmoothing capacitor, the detecting diode being mounted onto themulti-layered module, and the smoothing capacitor being formed bycapacitor electrodes opposing via a dielectric layer inside themulti-layered module.

[0025] The high-frequency amplifier comprises an amplifier circuitcomprising a transistor, an input-matching circuit connected to theinput terminal of the amplifier circuit, an output-matching circuitconnected to the output terminal of the amplifier circuit, each of theinput-matching circuit and the output-matching circuit comprising acapacitor and an inductor. It is preferable that the transistor of theamplifier circuit is mounted onto the multi-layered module, and that theinductor is formed as a distributed constant line inside themulti-layered module. The capacitor is preferably formed by capacitorelectrodes opposing via a dielectric layer inside the multi-layeredmodule. The transistor of the amplifier circuit is preferably a fieldeffect transistor. The high-frequency amplifier is preferablyconstituted by a gallium arsenide GaAs transistor and mounted onto themulti-layered module.

[0026] The wireless communications device of the present inventioncomprises the above high-frequency composite part.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 is a block diagram showing one example of thehigh-frequency composite part of the present invention;

[0028]FIG. 2 is a block diagram showing one example of a transmittingsignal control means used in the high-frequency composite part of thepresent invention;

[0029]FIG. 3 is a view showing an equivalent circuit of another exampleof the transmitting signal control means used in the high-frequencycomposite part of the present invention;

[0030]FIG. 4 is a view showing an equivalent circuit of a fartherexample of the transmitting signal control means used in thehigh-frequency composite part of the present invention;

[0031]FIG. 5 is a view showing an equivalent circuit of a furtherexample of the transmitting signal control means used in thehigh-frequency composite part of the present invention;

[0032]FIG. 6 is a Smith chart showing the impedance characteristics in asubstantially short-circuited state and a substantially open state;

[0033]FIG. 7(a) is a Smith chart showing the impedance Zp1 of thehigh-frequency amplifier viewed from the connection point P0 in thetransmitting signal control means of FIG. 3, while the high-frequencyamplifier is at a stop;

[0034]FIG. 7(b) is a Smith chart showing the impedance Zip1 of thetransmitting signal control means of FIG. 3 viewed from the connectionpoint IP1 while the high-frequency amplifier is at a stop;

[0035]FIG. 8 is a view showing an equivalent circuit of one example ofthe high-frequency amplifier used in the high-frequency composite partof the present invention;

[0036]FIG. 9 is a block diagram showing one example of the receivingsignal control means used in the high-frequency composite part of thepreset invention,

[0037]FIG. 10 is a view showing one example of an equivalent circuit ofthe receiving signal control means used in the high-frequency compositepart of the present invention;

[0038]FIG. 11 (a) is a Smith chart showing the impedance Zp2 of the bandpass filter used in the high-frequency composite part of the presentinvention;

[0039]FIG. 11(b) is a Smith chart showing the impedance Zip1 of thereceiving signal control means in the high-frequency composite part ofthe present invention;

[0040]FIG. 12 is a view showing an equivalent circuit of a furtherexample of the receiving signal control means used in the high-frequencycomposite part of the present invention;

[0041]FIG. 13 is a view showing an equivalent circuit of one example ofthe high-frequency composite part of the present invention;

[0042]FIG. 14 is a view showing an equivalent circuit of a furtherexample of the high-frequency composite part of the present invention;

[0043]FIG. 15 is a block diagram showing one example of the dual-band,high-frequency composite part of the present invention;

[0044]FIG. 16 is a block diagram showing one example of a duplexer usedin the dual-band, high-frequency composite part of the presentinvention;

[0045]FIG. 17 is a view showing an equivalent circuit of one example ofthe dual-band, high-frequency composite part of the present invention;

[0046]FIG. 18 is a top view showing the appearance of the integralmulti-layered module containing the dual-band, high-frequency compositepart;

[0047]FIG. 19 is an open view showing a circuit structure of each layerconstituting a multi-layered module for the dual-band, high-frequencycomposite part of the present invention;

[0048]FIG. 20 is a partially cross-sectional view showing an integralmulti-layered module containing the high-frequency composite part of thepresent invention; and

[0049]FIG. 21 is a view showing an equivalent circuit of theconventional high-frequency composite part.

THE BEST MODE FOR CARRYING OUT THE INVENTION

[0050] The preferred embodiments of the present invention are explainedin detail below referring to the attached figures. For the simplicity ofexplanation, EGSM (transmitting frequency: 880-915 MHz, receivingfrequency: 925-960 MHz) is taken as an example of the first signalfrequency band f1 . Of course, the present invention can be applied toother communications systems such as a DCS1800 system (transmitting TX:1710-1785 MHz, receiving RX: 1805-1880 MHz), a PCS system (transmittingTX 1850-1910 MHz, receiving RX: 1930-1990 MHz), etc.

[1] Constitution of High-Frequency Composite Part

[0051]FIG. 1 is a block diagram showing one example of thehigh-frequency composite part of the present invention, which may becalled “high-frequency switch module.” This high-frequency compositepart is a single-band high-frequency composite part comprising atransmitting signal control means 2 between a connection point IP1 and atransmitting circuit TX, and a receiving signal control means 3 betweenthe connection point IP1 and a receiving circuit RX.

[0052] (A) Transmitting Signal Control Means

[0053] As shown in FIG. 2, the transmitting signal control means 2comprises a first phase-shifting circuit 5 connected between theconnection point IP1 and the transmitting circuit TX, and ahigh-frequency amplifier 4. The high-frequency amplifier 4 has suchimpedance characteristics that its impedance is substantially 50 Ω atwork in a frequency band of a transmitting signal, and that it is in asubstantially short-circuited state at a stop in a frequency band of areceiving signal. The first phase-shifting circuit 5 connected to thehigh-frequency amplifier 4 controls the angle of phase moved such thatthe impedance of the transmitting signal control means 2 viewed from theside of the connection point IP1 is a substantially open state.

[0054] The term “substantially short-circuited state” means a case wherethe real number part R is adjusted to 15 Ω or less, and a case where anabsolute value of the imaginary number part X is adjusted to 15 Ω orless, in the impedance Z expressed by Z=R+jX. Expressed in a Smith chartof FIG. 6, for instance, the “substantially short-circuited state”corresponds to a hatched region on the left side. Also, the term“substantially open state” means a case where the real number part R isadjusted to 150 Ω or more, and a case where an absolute value of theimaginary number part X is adjusted to 100 Ω or more, in the impedance Zexpressed by Z=R+jX. Expressed in a Smith chart, the “substantially openstate” corresponds to a hatched region on the right side in FIG. 6.

[0055] The high-frequency amplifier 4 is controlled to be in asubstantially short-circuited state (in a hatched portion on the leftside in the Smith chart of FIG. 6) at a stop in a frequency band of areceiving signal. The first phase-shifting circuit 5 is controlled suchthat the impedance of the transmitting signal control means 2 viewedfrom the side of the connection point IP1 is in a hatched portion on theright side in the Smith chart of FIG. 6. With such a structure, areceiving signal leaking to the transmitting signal control means can bemade extremely small.

[0056]FIG. 3 shows one example of an equivalent circuit of thephase-shifting circuit 5. The phase-shifting circuit 5 is constituted bya distributed constant line 6 whose line length is substantially λ/4 ina frequency band (receiving frequency: 925-960 MHz) of a receivingsignal. This phase-shifting circuit is advantageous in that it has asimple structure. FIG. 7(a) shows the impedance Zp0 of thehigh-frequency amplifier 4 viewed from the connection point P0 in thetransmitting signal control means 2 of FIG. 3, and FIG. 7(b) shows theimpedance Zip1 TX of the transmitting signal control means 2 viewed fromthe connection point IP1. In this case, the high-frequency amplifier 4is at a state. As is clear from FIGS. 7(a) and (b), the impedance of thehigh-frequency amplifier 4 is in a substantially short-circuited statein a frequency band of a receiving signal, while the impedance of thetransmitting signal control means 2 viewed from the connection point IP1is in a substantially open state by the first phase-shifting circuit 5.

[0057]FIG. 4 is a block diagram showing another example of thephase-shifting circuit 5. In this phase-shifting circuit 5, capacitors7, 8 are connected to both sides of the distributed constant line 6. Thephase-shifting circuit 5 can have a shorter line length than whenconstituted by the distributed constant line 6 only, with advantagesthat it functions as a low-pass filter for attenuating harmonic signalsfrom the high-frequency amplifier 4.

[0058]FIG. 5 shows another example of the phase-shifting circuit 5. Thephase-shifting circuit 5 is a directional coupler comprising adistributed constant line 6 as a main line and a distributed constantline 7 as a sub-line. With this phase-shifting circuit 5, part of atransmitting signal from the high-frequency amplifier 4 is taken outfrom one end of the distributed constant line 7 constituting thephase-shifting circuit 5 (directional coupler), attenuated by aattenuator 16 comprising resistors 9, 10, 11 and supplied to thedetector 15. The attenuator 16 attenuates part of the transmittingsignal (high-frequency signal) to such electric power that can behandled by a circuit on the downstream side. After the above part oftransmitting signal is rectified by a detecting diode 12 in the detector15, it is subjected to voltage conversion by a smoothing capacitor 13and a load resistor 14 to generate a detection signal, which is suppliedto the control circuit 16. Compared with a control signal of apredetermined transmitting output level, the detection signal issubjected to feedback to a driver amplifier 81 to make this differencesmall, whereby it is controlled to a targeted transmitting output level.

[0059] In the present invention, as shown in FIG. 18, the distributedconstant line and the capacitor constituting the first phase-shiftingcircuit are formed by electrode patterns on a plurality of green sheetsmade of a dielectric material, and green sheets are multi-layered andsintered to form an integral multi-layered module 170, which constitutesa one-chip, high-frequency switch module.

[0060] With the attenuator constituted by chip resistors mounted ontothe multi-layered module, wires for connecting the phase-shiftingcircuit and the attenuator can be mounted onto the multi-layered module.In this case, the overall dimension of the high-frequency composite partcan be made smaller than when the attenuator is connected to a circuitboard onto which the high-frequency switch module is mounted. Also, withthe detector 15 constituted such that a chip resistor is mounted as aload resistor 14 onto the multi-layered module, that a smoothingcapacitor 13 is formed by capacitor electrodes opposing each other via adielectric layer inside the multi-layered module, and that a detectingdiode 12 is mounted onto the multi-layered module, the overall dimensionof the high-frequency composite part can be made smaller than when thedetector 15 is connected to the circuit board separately from themulti-layered module.

[0061] Because a transistor and MMIC (microwave monolithic integratedcircuit) constituting the high-frequency amplifier 4 have large powerconsumption and heat generation, a temperature-sensing device(thermistor) for compensating temperature variations may be attached tothe detector 15 to control the temperature of the detector 15.

[0062]FIG. 8 shows one example of an equivalent circuit of thehigh-frequency amplifier 4. The high-frequency amplifier 4 comprises aninput-matching circuit 23 comprising an inductor 19 and a capacitor 18,an output-matching circuit 26 comprising an inductor 20 and a capacitor21, and stabilizing circuits 24, 25 each comprising a resistor, acapacitor and an inductor for preventing oscillation, and a field effecttransistor 27.

[0063] With the field effect transistor 27 constituting thehigh-frequency amplifier 4 mounted onto the multi-layered module 170,the inductors constituting the input-matching circuit 23 and theoutput-matching circuit 26 formed by distributed constant lines, and thecapacitors formed by capacitor electrodes opposing each other via adielectric layer inside the multi-layered module, the overall dimensionof the device can be made small.

[0064] As shown in FIG. 20, the multi-layered module 170 may be providedwith a cavity 202 in which the transistor 27 constituting thehigh-frequency amplifier and a semiconductor chip 201 made of galliumarsenide GaAs are mounted. With the opening of the cavity 202 properlysealed with plastics such as epoxy resins or covered by a cap 203, thetop surface of the multi-layered module 170 can be made flat to make iteasy to handle the multi-layered module 170, thereby stabilizing thecharacteristics of the high-frequency amplifier.

[0065] The transistor and MMIC constituting the high-frequency amplifier4 have large power consumption and thus large heat generation, withgrounded inductance having larger influence on electricalcharacteristics at higher frequencies. Accordingly, it is important thatthey have good heat dissipation and sufficiently low groundedinductance. Therefore, the multi-layered module may be provided withvia-holes immediately under the high-frequency amplifier 4, such thatheat generated from the high-frequency amplifier 4 is dissipated to thecircuit board through via-holes. Also, to achieve high heat dissipationand low grounded inductance, metal columns called “bumps” may be formedon the transistor electrodes on the semiconductor chip to use flip chipbonding for bonding the bumps of the semiconductor chip and theelectrodes on the circuit board.

[0066] (B) Receiving Signal Control Means

[0067] As shown in FIG. 9, the receiving signal control means 3comprises a second phase-shifting circuit 50 connected between theconnection point IP1 and the receiving circuit RX, and a band passfilter 51. The second phase-shifting circuit 50 connected to the bandpass filter 51 controls the phase angle of the high-frequency signal, tokeep the impedance of the receiving signal control means 3 viewed fromthe side of the connection point IP1 in a substantially open state.

[0068]FIG. 10 shows one example of an equivalent circuit of aphase-shifting circuit 50, in which the second phase-shifting circuit isconstituted by a distributed constant line. Usable as the band passfilter 51 is a surface acoustic wave filter, a multi-layered-typedielectric filter, a coaxial resonator filter or a bulk-wave filter.FIG. 11(a) shows the impedance Zp2 of a surface acoustic wave filter(SAW). The surface acoustic wave filter has impedance of substantially50 Ω in a receiving frequency passband of a receiving signal, while ithas low impedance in a transmitting frequency of a transmitting signal.The phase-shifting circuit 50 is constituted by a distributed constantline 52 having a line length of substantially 5λ/16 in a frequency bandof a transmitting signal (transmitting frequency: 880-915 MHz), and asshown in FIG. 11(b), the impedance Zip1 RX of the receiving signalcontrol means 3 corresponds to a substantially open state in a frequencyband of a transmitting signal.

[0069]FIG. 13 shows an equivalent circuit of the high-frequencycomposite part comprising a combination of a receiving signal controlmeans 3 and a transmitting signal control means 2. With such astructure, it is possible to extremely reduce the leakage of atransmitting signal to the receiving signal control means with itsstructure extremely simplified. Without diodes, there is decreasedinsertion loss between the transmitting circuit TX and the antenna ANT,resulting in decrease in current consumption.

[0070]FIG. 12 shows another example of an equivalent circuit of thereceiving signal control means 3. In the receiving signal control means3, a distributed constant line 55 is connected between the connectionpoint IP1 and RX, with one end of the distributed constant line 55 onthe side of the receiving circuit RX connected to the cathode of a diode57, and with a capacitor 58 connected between the anode of the diode 57and a ground. A series circuit comprising an inductor 59 and a resistor60 is connected between the anode of the diode 57 and the controlcircuit VC1. The resistor 60 controls current while the diode 57 is inan ON state. The inductor 59 functions to enlarge the impedance of thecontrol circuit VC1 viewed from the side of the anode of the diode 57,though the inductor 59 may be omitted. In this embodiment, thedistributed constant line 55 has such a line length that its resonancefrequency is in a frequency band of a transmitting signal of EGSM.

[0071]FIG. 14 shows one example of an equivalent circuit of thehigh-frequency composite part comprising a combination of the receivingsignal control means 3 and the transmitting signal control means 2. Thehigh-frequency composite part is provided with a current path (notshown) for leading current to a ground. In this high-frequency switchmodule, the diode 57 is turned on by forward bias voltage from thecontrol circuit VC1 and resonates by the grounding of the distributedconstant line 55 by the diode 57 to make the impedance of the receivingcircuit RX viewed from the side of the connection point IP1 extremelylarge, so that the transmitting signal of the transmitting circuit TX isnot transmitted to the receiving circuit RX.

[0072] (C) Operation

[0073] The high-frequency switch module of the present invention selectstransmitting or receiving in the transmitting/receiving system by theoperation of the high-frequency amplifier 4. With respect to thehigh-frequency composite part having an equivalent circuit shown inFIGS. 13 and 14, operation will be explained in detail below.

[0074] (1) High-frequency Composite Part of FIG. 13

[0075] (a) EGSM TX Mode

[0076] When the transmitting circuit TX is connected to the antenna ANT,the high-frequency amplifier 4 is at work. Because the high-frequencyamplifier 4 has impedance of substantially 50 Ω at work, thetransmitting signal is sent to the connection point IP1 via thedistributed constant line. Because the impedance of the receiving signalcontrol means 3 viewed from the connection point IP1 in a frequency bandof a transmitting signal is a substantially open state (high impedance)by the distributed constant line 52 and the surface acoustic wave filter51, the transmitting signal is sent to the antenna ANT without leakingto the receiving circuit.

[0077] (b) EGSM RX Mode

[0078] When the antenna ANT is connected to the receiving circuit RX,the high-frequency amplifier 4 is at a stop. Though the impedance of thehigh-frequency amplifier 4 is in a substantially short-circuited stateat a stop in a frequency of a receiving signal, the impedance of thetransmitting signal control means 2 viewed from the connection point IP1in a frequency band of a receiving signal is in a substantially openstate (high impedance) by the distributed constant line 5 connected tothe high-frequency amplifier 4. Therefore, the receiving signal does notleak to the transmitting circuit TX. The surface acoustic wave filter 51constituting the receiving signal control means has impedance ofsubstantially 50 Ω in a frequency of a receiving signal. Therefore, thereceiving signal passes through the distributed constant line 52 and thesurface acoustic wave filter 51 to the receiving circuit RX.

[0079] Because the high-frequency composite part of the presentinvention can achieve high isolation characteristics with an extremelysimple structure, and because a diode can be omitted in both of thetransmitting system and the receiving system, it is possible to suppressthe insertion loss of the transmitting signal. Because diodes 77, 78,capacitors 70, 71, 74, 79, an inductor 76, etc. necessary in theconventional high-frequency composite part as shown in FIG. 21 can beomitted, the high-frequency composite part can be miniaturized. Inaddition, the high-frequency amplifier 4 and the band pass filter 51separately mounted onto a conventionally circuit board can beintegrated, the overall dimension of the high-frequency composite partcan be made further smaller. As a result, the wireless communicationsdevice comprising the high-frequency composite part can also be madesmall in size and reduced in weight.

[0080] (2) High-frequency Composite Part of FIG. 14

[0081] (a) EOSM TX Mode

[0082] To connect the transmitting circuit TX to the antenna ANT, thehigh-frequency amplifier 4 is operated, and positive voltage is givenfrom the control circuit VC1 to turn on the diode 57. Because theimpedance of the high-frequency amplifier 4 is substantially 50 Ω atwork, the transmitting signal passes through the distributed constantline to the connection point IP1. Positive voltage provided from thecontrol circuit VC1 is applied to the diode 57 with its DC signal cut bythe capacitors 56, 58, 61 and the capacitor 22 of the high-frequencyamplifier 4, to turn the diode 57 in an ON state. As a result, the diode57 and the capacitor 58 are resonated with the distributed constant line55 grounded at high frequencies, resulting in the extremely largeimpedance of the receiving circuit RX viewed from the side of theconnection point IP1, which leads the transmitting signal to the antennaANT without leaking to the receiving circuit.

[0083] (b) EGSM RX Mode

[0084] To connect the antenna ANT to the receiving circuit RX, thehigh-frequency amplifier 4 stops, and zero voltage is provided to thecontrol circuit VC1. Though the impedance of the high-frequencyamplifier 4 is in a substantially short-circuited state at a stop in afrequency of a receiving signal, the impedance of the transmittingsignal control means 2 viewed from the side of the connection point IP1in a frequency band of a receiving signal is in a substantially openstate (high impedance) by the distributed constant line 5 connected tothe high-frequency amplifier 4, so that the receiving signal does notleak to the transmitting circuit IX. With zero voltage applied to thecontrol circuit VC1, the diode 57 is in an OFF state. With the diode 57in an OFF state, the connection point IP1 is connected to the receivingcircuit RX via the distributed constant line 55, so that the receivingsignal is transmitted to the receiving circuit RX without leaking to thetransmitting circuit TX.

[0085] Because in the high-frequency composite part of the presentinvention, high isolation characteristics can be achieved with anextremely simple structure, and diodes can be omitted from thetransmitting system as described above, the insertion loss of thetransmitting signal can be suppressed. Because the diode 77, etc.necessary in the conventional high-frequency switch module are not used,the high-frequency switch module can be miniaturized. In addition, thehigh-frequency amplifier 4 that used to be separately mounted onto theconventional circuit board can be integrated, the overall dimension ofthe device can be made small, so that the wireless communications devicecomprising the high-frequency composite part can be made small in sizeand reduced in weight.

[2] Specific Examples of High-Frequency Composite Part

[0086]FIG. 15 is a block diagram showing one example of thehigh-frequency composite part according to the preferred embodiment ofthe present invention, and FIG. 17 is a view showing an equivalentcircuit of one example of the high-frequency composite part according tothe preferred embodiment of the present invention. This embodiment isconcerned about a dual-band, high-frequency composite part for switchinga transmitting circuit and a receiving circuit in a plurality ofdifferent transmitting/receiving systems. For the simplicity ofexplanation, EGSM (transmitting frequency: 880-915 MHz, receivingfrequency: 925-960 MHz) is taken as an example of the first signalfrequency band f1, and DCS1800system (transmitting IX: 1710-1785 MHz,receiving RX: 1805-1880 MHz) is taken as an example of the second signalfrequency band f2.

[0087] (A) First and Second Filter Circuits

[0088] The first and second filter circuits 101, 102 connected to theantenna ANT are each constituted by a distributed constant line and acapacitor. A low-pass filter is used as the first filter circuit 101 forallowing the transmitting and receiving signals of EGSM to pass throughwhile attenuating the transmitting and receiving signals of DCS1800, anda high-pass filter is used as the second filter circuit 102 for allowingthe transmitting and receiving signals of DCS 1800 to pass through whileattenuating the transmitting and receiving signals of EGSM.

[0089] The low-pass filter 101 is constituted by a distributed constantline 401 and a capacitor 403 connected in parallel, a capacitor 404connected to a ground, a distributed constant line 402 and a capacitor405 connected in parallel, and a capacitor 406 connected to a ground.The high-pass filter 102 is constituted by a distributed constant line407 and a capacitor 408 connected in parallel, a distributed constantline 409 connected to a ground, and a capacitor 410 connected in seriesto the distributed constant line 407 and the capacitor 408. With such astructure, receiving signals of the first transmitting/receiving systemand the second transmitting/receiving system can be branched In additionto the above structure, the first and second filter circuits 101, 102may have the following structures (a)-(h):

[0090] (a) A structure in which the first filter circuit 101 isconstituted by a low-pass filter, and the second filter circuit 102 isconstituted by a notch filter;

[0091] (b) A structure in which the first filter circuit 101 isconstituted by a notch filter, and the second filter circuit 102 isconstituted by a bandpass filter;

[0092] (c) A structure in which the first filter circuit 101 isconstituted by a low-pass filter, and the second filter circuit 102 isconstituted by a bandpass filter;

[0093] (d) A structure in which the first filter circuit 101 isconstituted by a notch filter, and the second filter circuit 102 isconstituted by a notch filter;

[0094] (e) A structure in which the first filter circuit 101 isconstituted by a notch filter, and the second filter circuit 102 isconstituted by a high-pass filter;

[0095] (f) A structure in which the first filter circuit 101 isconstituted by a bandpass filter, and the second filter circuit 102 isconstituted by a bandpass filter;

[0096] (g) A structure in which the first filter circuit 101 isconstituted by a bandpass filter, and the second filter circuit 102 isconstituted by a notch filter; and

[0097] (h) A structure in which the first filter circuit 101 isconstituted by a bandpass filter, and the second filter circuit 102 isconstituted by a high-pass filter.

[0098] (B) Signal Line Control Circuit on EGSM Side

[0099] (1) Signal Line Control Circuit on the Side of EGSM

[0100] The first signal line control circuit SW1 and the second signalline control circuit SW2 are placed on the downstream side of the firstand second filter circuits 101, 102, respectively, the first signal linecontrol circuit SW1 for switching the transmitting circuit TX1 and thereceiving circuit RX1 of EGSM comprising a high-frequency amplifier, adiode and a distributed constant line as main constituents, and thesecond signal line control circuit SW2 for switching the transmittingcircuit TX2 and the receiving circuit RX2 of DCS1800 comprising a diodeand a distributed constant line as main constituents.

[0101] The first signal line control circuit SW1 for switching thetransmitting circuit TX1 and the receiving circuit RX1 of EGSM comprisesa diode 57 and two distributed constant lines 5, 55 and a high-frequencyamplifier 4 as main constituents. The distributed constant line 5 isdisposed between the first connection point IP1 and transmitting circuitTX1 in a line for the transmitting and receiving signals of EGSM, andthe high-frequency amplifier 4 is connected in series to the downstreamside of the distributed constant line 5. The distributed constant line 5has a line length of substantially λ/4 in a frequency band of areceiving signal of EGSM. The impedance characteristics of thehigh-frequency amplifier 4 are such that its impedance is substantially50 Ω at work while it is substantially short-circuited at a stop. Thedistributed constant line 55 is connected between the first connectionpoint IP1 and RX1, with one end of the distributed constant line 55 onthe side of the receiving circuit RX1 connected to a cathode of thediode 57, with a capacitor 58 connected between the anode of the diode57 and ground, and with a series circuit comprising an inductor 59 and aresistor 60 connected between the anode of the diode 57 and a controlcircuit VC1. The distributed constant line 55 has such a line lengththat its resonance frequency is in a frequency band of a transmittingsignal of EGSM.

[0102] When the receiving signal of EGSM is sent to the receivingcircuit RX1, the impedance characteristics of the high-frequencyamplifier 4 at a stop correspond to a substantially short-circuitedstate without the distributed constant line 5, so that the receivingsignal is absorbed in the high-frequency amplifier 4. However, becauseof the distributed constant line 5, the impedance viewed from the firstconnection point IP1 is in a substantially open state, to that thereceiving signal is sent to the receiving circuit RX1.

[0103] Though not shown in FIG. 17, the high-frequency amplifier 4comprises a capacitor for shutting off the DC signal. With thisstructure, the DC component from the high-frequency amplifier 4 does notflow into the receiving circuit RX1, and the DC signal in voltageapplied by the control circuit VC1 to turn on the diode 57 does not flowinto the transmitting circuit TX1.

[0104] (C) Signal Line Control Circuit on the Side of DCS1800

[0105] The signal line control circuit SW2 for switching the receivingcircuit RX2 and the transmitting circuit TX2 of DCS 1800 comprises twodiodes 306, 309 and two distributed constant lines 301, 307 as mainconstituents. The diode 306 is placed between the second connectionpoint IP2 through which the transmitting signal and the receivingsignals of DCS1800 pass and the transmitting circuit TX2, with its anodeconnected to the connection point IP2, and with the distributed constantline 301 connected between the cathode of the diode 306 and the ground.The distributed constant line 307 is connected between the connectionpoint IP2 and the receiving circuit RX2, with one end of the distributedconstant line 307 on the side of the receiving circuit RX2 connected tothe cathode of the diode 309, with the capacitor 310 connected betweenthe anode of the diode 309 and the ground, and with the series circuitcomprising an inductor 311 and a resistor 312 connected between theanode of the diode 309 and the control circuit VC2. The distributedconstant line 301 has such a line length that resonance frequency withthe capacitor 302 is in a frequency band of a transmitting signal ofDCS1800.

[0106] The low-pass filter circuit is placed between the transmittingcircuit IX2 and the connection point IP2. This low-pass filter circuitis preferably a π-type low-pass filter constituted by a distributedconstant line 305 and capacitors 302, 303, 304. The low-pass filtercircuit is compositely formed between elements constituting the signalline control circuits, though the low-pass filter circuit may bedisposed on the input or output side of the signal line control circuit.

[0107] To connect the second transmitting circuit TX2 to the secondfilter circuit 102, positive voltage is applied from the control circuitVC2. With a DC signal removed by capacitors 300, 308, 310, 304, 303,302, and 410, the positive voltage provided from the control circuit VC2is applied to a circuit comprising diodes 306, 309 to turn them on. Whenthe diode 306 is in an ON state, impedance is low between the secondtransmitting circuit TX) and the connection point IP2. With the diode309 in an ON state and the capacitor 310, the distributed constant line307 is grounded at high frequencies, causing resonance, resulting in theextremely high impedance of the second receiving circuit RX2 viewed fromthe connection point IP2. Accordingly, the transmitting signal from thesecond transmitting circuit TX2 is transmitted to the second filtercircuit 102 without leaking to the second receiving circuit RX2.

[0108] When the second receiving circuit RX2 is connected to the secondfilter circuit 102, zero voltage is applied to the control circuit VC2,putting the diodes 306, 309 in an OFF state. With the diode 309 in anOFF state, the connection point IP2 and the second receiving circuit RX2are connected via the distributed constant line 307. With the diode 306in an OFF state, the impedance of the second transmitting circuit TX2 ishigh when viewed from the side of the connection point IP2. Accordingly,the receiving signal from the second filter circuit 102 is sent to thesecond receiving circuit RX2 without leaking to the second transmittingcircuit TX 2.

[0109] The above control of high-frequency signal lines can be carriedout by controlling the operation states of the control circuits VC1, VC2and the high-frequency amplifier as shown in Table 1 to change thetransmitting/receiving modes of EGSM and DCS 1800. TABLE 1High-Frequency Mode VC1 VC2 Amplifier EGSM TX High Low At work EGSM RXLow Low At stop DCS1800 TX Low High At stop DCS1800 RX Low Low At stop

[0110] (D) Multi-Layered Structure of High-Frequency Composite Part

[0111]FIG. 18 is a plan view showing the high-frequency composite partof the present embodiment, and FIG. 19 is a view showing the structureof each layer constituting the multi-layered module of FIG. 18. In thisembodiment, the first and second filter circuits, the low-pass filtercircuits, the distributed constant line of the signal line controlcircuit and the inductors and capacitors of the matching circuit of thehigh-frequency amplifier are formed in the multi-layered module, whilediodes, semiconductor chips of the high-frequency amplifier, andhigh-capacitance capacitors, resistors and inductors that cannot becontained in the multi-layered module are mounted as chip parts onto themulti-layered module, thereby constituting a one-chip-type, dual-band,high-frequency composite part.

[0112] This multi-layered module is produced by forming green sheets of10 μm to 500 μm in thickness made of a low-temperature sinterableceramic dielectric material, printing an Ag-based conductive paste oneach green sheet to form a desired electrode pattern, integrallylaminating a plurality of green sheets with electrode patterns, and thensintering the resultant laminate. Most line electrodes preferably have awidth of 100 μm to 400 μm. The internal structure of the multi-layeredmodule will be explained in the order of lamination.

[0113] The lowermost green sheet 13 is provided substantially on anentire surface with a ground electrode 120, which has extensions forconnecting to terminal electrodes formed on the side surface.

[0114] A green sheets 12 provided with capacitor electrodes 122, 123 anda line electrode 121 for constituting the input-matching circuit andoutput-matching circuit of the high-frequency amplifier, a green sheet11 provided with five line electrodes 126, 127, 128, 129, 130 andcapacitor electrodes 124, 125, and a green sheet 10 provided with fourline electrodes 47, 48, 133, 134 are successively laminated on the greensheet 13. laminated thereon are a green sheet 9 provided with fivethrough-hole electrodes (shown by black circles in the view), and then agreen sheet 8 provided with five through-hole electrodes and a groundelectrode 32.

[0115] Line electrodes are connected in regions sandwiched by two groundelectrodes 120, 32. Specifically, the line electrodes 126 and 134 areconnected via through-hole electrodes to constitute part of thedistributed constant line 5; the line electrodes 129 and 133 areconnected via through-hole electrodes to constitute the distributedconstant line 55; the line electrodes 128 and 48 are connected viathrough-hole electrodes to constitute the distributed constant line 307;and the line electrodes 127 and 47 are connected via through-holeelectrodes to constitute the distributed constant line 301. The lineelectrode 121 constitutes a distributed constant line 20 for theoutput-matching circuit 26 of the high-frequency amplifier 4; thecapacitor electrode 122 and the ground electrode 120 constitutes thecapacitor 21 of the output-matching circuit 26; the capacitor electrode123 and the ground electrode 120 constitutes a capacitor 18 for theinput-matching circuit 23 of the high-frequency amplifier 4; thecapacitor electrode 122 and the capacitor electrode 124 constitutes aDC-cutting capacitor 22 of the high-frequency amplifier 4; and thecapacitor electrode 123 and the capacitor electrode 125 constitutes aDC-cutting capacitor 17 of the high-frequency amplifier 4. The lineelectrode 130 constitutes the distributed constant line 19 of theinput-matching circuit 23.

[0116] In this embodiment, capacitors for the input-matching circuit 23and output-matching circuit 26 of the high-frequency amplifier 4 areformed in multi-layered module, though the above capacitors may bemounted onto the multi-layered module as chip capacitors to haveproperly desired capacitance if fine adjustment is needed.

[0117] A green sheet 7 laminated on the green sheet 8 is provided withcapacitor electrodes 136, 137, 138, 139, 140, 141, 142 and 143. A greensheet 6 laminated thereon is provided with capacitor electrodes 144,145, 147 and a ground electrode 146. A green sheet 5 laminated thereonis provided with capacitor electrodes 148, 149, 150.

[0118] laminated thereon are a green sheet 4 provided with lineelectrodes 151, 152, 153, 154, 155, a green sheet 3 provided with lineelectrodes 156, 157, 158 and connection lines, and a green sheet 2provided with through-hole electrodes. The uppermost green sheet 1 isprovided with lands for mounting elements.

[0119] Capacitor electrodes 136, 137, 138, 139, 140, 141, 143 on thegreen sheet 7 laminated on the green sheet 8 having an upper groundelectrode 32 constitutes capacitors with the ground electrode 32.Specifically, the capacitor electrode 143 constitutes a capacitor 404,the capacitor electrode 136 constitutes a capacitor 406; the capacitorelectrode 140 constitutes a capacitor 58; the capacitor electrode 138constitutes a capacitor 302; the capacitor electrode 139 constitutes acapacitor 303; and the capacitor electrode 141 constitutes a capacitor310.

[0120] Capacitor electrodes formed on the green sheets 5, 6, 7constitute capacitance with each other. Specifically, a capacitor 410 isconstituted between the capacitor electrodes 142 and 147; a capacitor408 is constituted between the capacitor electrodes 147 and 150, acapacitor 405 is constituted between the capacitor electrodes 137, 136and 144; a capacitor 304 is constituted between the capacitor electrodes138, 139 and 145. Further, parasitic capacitance between the lineelectrodes 155 and 158 constitutes a capacitor 403 in the equivalentcircuit.

[0121] Line electrodes 155, 158 constitute the distributed constant line401 in the green sheets 3, 4; line electrodes 154, 157 constitute thedistributed constant line 407, line electrode 153 constitute thedistributed constant line 409; line electrodes 152, 156 constitute thedistributed constant line 305; and a line electrode 151 constitutes thedistributed constant line 402. Lines on the green sheet 3 except for theline electrodes 156, 157, 158 are wiring lines.

[0122] These green sheets are pressure-bonded and integrally sintered toprovide a multi-layered module 100 of 9.6 mm×5.0 mm×1.0 mm in outerdimension. This multi-layered module 100 is provided with terminalelectrodes on the side surface. As shown in FIG. 18, mounted onto thismulti-layered module are diodes 57, 306, 309, a transistor 27, chipcapacitors 56, 308, 411, chip inductors 59, 311 and capacitors,resistors and inductors for constituting the stabilizing circuit of thehigh-frequency amplifier. Incidentally, GND denotes a ground terminal.

[0123] In this embodiment, distributed constant lines for the first andsecond signal line control circuits are formed in the multi-layeredmodule in regions sandwiched by the ground electrodes. With thisstructure, interference between the signal line control circuits, thebranching circuits (diplexer) and the low-pass filter circuits isprevented. Because regions sandwiched by the ground electrodes arelocated in a lower portion of the multi-layered module, it is easy toget a ground potential. In this embodiment, the multi-layered module isprovided with each terminal on the side surface to have such a structureas to enable surface mounting. The terminals on the side surface are anANT terminal, a TX2 terminal of DCS 1800, a TX1 terminal of EGSM, an RX1terminal of EGSM, an RX2 terminal of DCS1800, a ground terminal GND, andcontrol terminals VC1, VC2. In place of the terminals on the sidesurface, internal wiring may be led to the bottom surface of themulti-layered module via through-holes as terminals of BGA (Ball GridArray), LGA (Land Grid Array), etc.

[0124] When the high-frequency composite part of the present inventionis used for a dual-band mobile phone, small battery consumption has beenconfirmed, resulting in mobile phones with low current consumption. Aslong as the high-frequency composite part comprises a combination of ahigh-frequency amplifier and a phase-shifting circuit as a transmittingsignal control means, it is within the range of the present invention

[0125] Though the structure and operation of the high-frequencycomposite part of the present invention has been explained with respectto the dual-band system of EGSM and DCS1800, the use of a duplexercomprising a combination of two filters as shown in FIG. 16 in place ofthe second signal line control circuits can provide a dual-modehigh-frequency composite part, for instance, for a TDMA system such asEGSM and a CDMA system such as WCDMA (wideband CDMA), and a wirelesscommunications device such as a mobile phone, etc. comprising such ahigh-frequency composite part.

What is claimed is:
 1. A high-frequency composite part connected among atransmitting circuit, a receiving circuit and an antenna for controllingthe connection between said transmitting circuit and said antenna, andthe connection between said receiving circuit and said antenna,comprising a transmitting signal control means comprising a firstphase-shifting circuit and a high-frequency amplifier between saidantenna and said transmitting circuit, said high-frequency amplifier andsaid first phase-shifting circuit being integrated in a multi-layeredmodule constituted by a plurality of dielectric layers.
 2. Thehigh-frequency composite part according to claim 1, wherein said firstphase-shifting circuit keeps the impedance characteristics of saidtransmitting signal control means in a substantially open state in afrequency band of a receiving signal, while said high-frequencyamplifier is at a stop.
 3. The high-frequency composite part accordingto claim 1 or 2, wherein said high-frequency amplifier has suchimpedance characteristics that it is in a substantially short-circuitedstate at a stop in a frequency band of a receiving signal.
 4. Thehigh-frequency composite part according to any one of claims 1-3,wherein said first phase-shifting circuit comprises a distributedconstant line.
 5. The high-frequency composite part according to claim4, further comprising a directional coupler for branching out part of atransmitting signal amplified by said high-frequency amplifier, a mainline of said directional coupler being part of a distributed constantline of said first phase-shifting circuit.
 6. The high-frequencycomposite part according to claim 5, further comprising a detector fordetecting part of a branched transmitting signal.
 7. The high-frequencycomposite part according to claim 6, wherein said detector comprises adetecting diode and a smoothing capacitor, said detecting diode beingmounted onto said multi-layered module, and said smoothing capacitorbeing formed by capacitor electrodes opposing via said dielectric layerin said multi-layered module.
 8. The high-frequency composite partaccording to any one of claims 1-7, wherein said high-frequencyamplifier comprises an amplifier circuit comprising a transistor, aninput-matching circuit connected to the input side of said amplifiercircuit, and an output-matching circuit connected to the output side ofsaid amplifier circuit, each of said input-matching circuit and saidoutput-matching circuit comprising a capacitor and an inductor, saidtransistor of said amplifier circuit being mounted onto saidmulti-layered module, and said inductor being formed as a distributedconstant line in said multi-layered module.
 9. The high-frequencycomposite part according to claim 8, wherein said capacitor is formed byelectrodes opposing via said dielectric layer in said multi-layeredmodule.
 10. The high-frequency composite part according to claim 8,wherein the transistor of said amplifier circuit is a field effecttransistor.
 11. The high-frequency composite part according to any oneof claims 1-9, wherein said high-frequency amplifier is constituted by agallium arsenide transistor mounted onto said multi-layered module. 12.The high-frequency composite part according to any one of claims 1-11,wherein a receiving signal means comprising a second phase-shiftingcircuit and a band pass filter is placed between said antenna and saidreceiving circuit.
 13. The high-frequency composite part according toclaim 12, wherein said second phase-shifting circuit keeps the impedancecharacteristics of said receiving signal control means in asubstantially open state in a frequency band of a transmitting signal.14. The high-frequency composite part according to claim 12 or 13,wherein said second phase-shifting circuit is disposed in saidmulti-layered module constituted by a plurality of dielectric layers.15. The high-frequency composite part according to claim 12, whereinsaid band pass filter is constituted by a surface acoustic wave filter,a multi-layered dielectric filter, a coaxial resonator filter or abulk-wave filter.
 16. The high-frequency composite part according to anyone of claims 1-11 , wherein a receiving signal control means is placedbetween said antenna and said receiving circuit, said receiving signalcontrol means comprising a distributed constant line and a diodeconnected between said distributed constant line and said receivingcircuit and grounded via a capacitor.
 17. The high-frequency compositepart according to claim 16, wherein the diode of said receiving signalcontrol means is mounted onto said multi-layered module, and saiddistributed constant line is formed in said multi-layered module.
 18. Ahigh-frequency composite part comprising a plurality of filter circuitshaving different passbands connected to an antenna terminal for handlinga plurality of transmitting/receiving systems having differentpassbands, wherein a transmitting signal control means comprising afirst phase-shifting circuit and a high-frequency amplifier is placed onthe downstream side of at least one filter circuit, said high-frequencyamplifier and said first phase-shifting circuit being integrally formedin said multi-layered module constituted by a plurality of dielectriclayers.
 19. The high-frequency composite part according to claim 18,wherein each of said first and second filter circuits is an LC circuitconstituted by an inductor and a capacitor, said inductor being formedas a distributed constant line in said multi-layered module.
 20. Thehigh-frequency composite part according to claim 19, wherein saidcapacitor is formed by electrodes opposing via said dielectric layer insaid multi-layered module.
 21. The high-frequency composite partaccording to claim 18, wherein while said high-frequency amplifier is ata stop, said first phase-shifting circuit keeps the impedancecharacteristics of said transmitting signal control means in asubstantially open state in a frequency band of a receiving signal. 22.The high-frequency composite part according to claim 18 or 21, whereinsaid high-frequency amplifier has such impedance characteristics that itis in a substantially short-circuited state at a stop in a frequencyband of a receiving signal.
 23. The high-frequency composite partaccording to any one of claims 18-22, wherein said first phase-shiftingcircuit comprises a distributed constant line.
 24. The high-frequencycomposite part according to claim 23, further comprising a directionalcoupler for branching part of a transmitting signal amplified by saidhigh-frequency amplifier, a main line of said directional coupler beingpart of a distributed constant line of said first phase-shiftingcircuit.
 25. The high-frequency composite part according to claim 24,further comprising a detector for detecting part of the branchedtransmitting signal.
 26. The high-frequency composite part according toclaim 25, wherein said detector comprising a detecting diode and asmoothing capacitor, said detecting diode being mounted onto saidmulti-layered module, said smoothing capacitor being formed by capacitorelectrodes opposing via said dielectric layer in said multi-layeredmodule.
 27. The high-frequency composite part according to any one ofclaims 18-26, wherein said high-frequency amplifier comprising anamplifier circuit comprising a transistor, an input-matching circuitconnected to the input side of said amplifier circuit, and anoutput-matching circuit connected to the output side of said amplifiercircuit, each of said input-matching circuit and said output-matchingcircuit comprising a capacitor and an inductor, the transistor of saidamplifier circuit being mounted onto said multi-layered module, and saidinductor being formed as a distributed constant line in saidmulti-layered module.
 28. The high-frequency composite part according toclaim 27, wherein said capacitor is formed by electrodes opposing viasaid dielectric layer in said multi-layered module.
 29. Thehigh-frequency composite part according to claim 27, wherein thetransistor of said amplifier circuit is a field effect transistor. 30.The high-frequency composite part according to any one of claims 18-27,wherein said high-frequency amplifier is constituted by a galliumarsenide transistor mounted onto said multi-layered module.
 31. Awireless communications device comprising the high-frequency compositepart according to any one of claims 1-30.
 32. The wirelesscommunications device according to claim 31, wherein it is a mobilephone.